RHI Certificate Drafting

Drafting of RHI-EC Air Quality Certificates – Updated Guidance on RHIEC website

Disclaimer: It is important to note, that due to a clarification in the RHI regulation some emission certificates listed on the HETAS AQ website at rhieclist.org.uk may no longer be acceptable to Ofgem when making a RHI application.
It is important for the applicant to check before submitting an application to Ofgem that the correct fuel classes and moisture content of the fuel is specified in accordance with these guidelines as appropriate. Failure to do this may result in the application being rejected until the required changes are made to the Emission certificate.

Update December 2018

Over recent months you may have been made aware of some of the recent adjustments to the way in which Ofgem require technical and performance information of biomass burning independent boilers to be confirmed on RHI audited air quality (AQ) emission certificates (EC).
As part of these process changes, Ofgem now request that all EC’s submitted either to HETAS for listing on the RHI-EC website, or sent directly to Ofgem as part of an application for the RHI, contain correct reference to the fuel classification of both the fuel used during AQ verification testing and the fuel referenced for future use in compliance with RHI requirements. This is to allow Ofgem to more effectively confirm fuels being burned on RHI compliant appliances and ensure applicants are meeting their ongoing obligations.
To ensure notified test laboratories, technical institutes, distributors and appliance manufacturers are made fully aware of what’s required of them when undertaking drafting procedures for publish of AQ certificates, below is a brief summary of the references now required against the applicable fuel standards used.
The updates mainly concern the information declared and further referenced under Part 3 “Fuels” section of the EC Currently a large proportion of manufacturers simply reference the types and range of compliant fuels referenced in Table 7 within the CE type test standard BS EN 303-5.

Fuel Classification

Moving forward, sections 3a & 3b should firstly clearly reference the type of fuel used during the testing process and range of fuels that can be used in compliance with the prescribed emission limits, clearly defining both its source and manufacturer type (i.e. wood log, wood chip, wood pellet) as appropriate.
As well as this, section 3 of the certificate should also clearly specify the correct classification of the fuel against the applicable fuel standard, dependent on the date of which the appliance is tested, which in most cases is likely to be either BS EN 14961 or BS EN 17225 graded fuel. It is important dependent on the type of the fuel that the sub clause is also referenced. (i.e. for wood logs BS EN 17225-5) and the fuel class as prescribed in Table 1 (Table 2 for Chip) of each standard is used. The applicable standards are as follows;

  • BS EN 17225-1 (supersedes BS EN 14961-1) – General Requirements
  • BS EN 17225-2 (supersedes BS EN 14961-2) – Wood Pellets (classes A1, A2 or B)
  • BS EN 17225-3 (supersedes BS EN 14961-3) – Wood Briquettes (classes A or B)
  • BS EN 17225-4 (supersedes BS EN 14961-4) – Wood Chips (classes A1, A2, B1 or B2)
  • BS EN 17225-5 (supersedes BS EN 14961-5) – Wood Logs (classes A1, A2 or B)

Note: These classes and specifications differ slightly to those prescribed within Table 7 of BS EN 303-5

Moisture Content

Sections 3c & 3d of the EC cover the prescribed moisture contents of both the tested fuel and maximum allowable moisture content of fuel that can be used on the appliance. Again, these moisture contents should be in compliance with the moisture limits specified in the table of the appropriate fuel’s standards listed above. It is also important noting that the minimum moisture contents specified in fuel specification standards may differ to those in BS EN 303-5, so only those documented in fuels standards should be used.

Emission Testing Dates

For appliances tested in accordance with BS EN 303-5:2012 version of the standard, the certificate should reference EN ISO 17225-(part number) if tested after 31st May 2015. Those appliances tested before this date are deemed acceptable to reference the EN 14961 series of standards as appropriate. If the test institute wishes to only reference the current version of the standard (EN ISO 17225) then this would also be deemed as compliant, even if tested before 31st May 2015.
In the event that the fuel cannot be classed in accordance with a biofuel sub-standard (commercial appliance or emissions tested against BS EN 13284 & BS EN 14792) then the certificate may reference the general biofuel standard (BS EN 17225-1), as long as they provide the origin, source and all normative details applicable for that fuel type as prescribed within the standard. Again, the fuel should be classed in accordance with EN ISO 17225-1 if the date of test is after 31/15/15.